Cities in U.S. will absorb the heat of climate change

May 8, 2014
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On Aug. 29, 2011, Teo Campbell stands on what used to be the bottom of the Bartonsville Covered Bridge over the Williams River in Rockingham, Vt., downstream from its original location after heavy rains from Hurricane Irene tore the bridge out. / File photo by Jim Cole, AP

by Doyle Rice, USA TODAY

by Doyle Rice, USA TODAY

The new National Climate Assessment released Tuesday didn't rank cities by which would be hit hardest, but here's a look at some communities that could be hard-hit by one aspect of climate change or another.

Quick outbursts of rain and snow, or "extreme precipitation," have increased by more than 70% in the past six decades in the northeastern U.S., according to the National Climate Assessment. This is the highest percentage increase of any location in the country.

Ferocious rainmakers like 2011's Hurricane Irene - one of the top weather disasters in Vermont's history - have become the signature of climate change in New England and the Northeast, afflicting older cities and towns built at a time of more modest rainfall.

The heavy rain and resulting floods are undermining aging bridges, eroding roads and overwhelming drainage systems. The frequency of heavy downpours is projected to continue to increase as the century progresses.

Heat waves -- Chicago; Dallas; St. Louis; and Kansas City

The rate of warming in the Midwest has markedly accelerated over the past few decades, according to the NCA. Between 1900 and 2010, the average Midwest air temperature increased by more than 1.5 degrees.

The frequency of major heat waves in the Midwest has also increased over the past six decades. For the entire nation, death increases 4% during heat waves compared with non-heat-wave days.

Heat stress is projected to increase as a result of both increased summer temperatures and humidity, the assessment predicts. One study projected an increase of between 166 and 2,217 extra deaths per year from heat-wave-related mortality in Chicago alone by later this century.

Climate change, resulting in more frost-free days and warmer seasonal air temperatures, can contribute to shifts in flowering time and pollen initiation from allergenic plant species, and increased carbon dioxide by itself can elevate production of plant-based allergens.

Wildfires -- Denver; Albuquerque; and Phoenix

Increased warming, drought and insect outbreaks - all caused by or linked to climate change - have increased wildfires and impacts to people and ecosystems across the rising populations of the Southwest, the assessment reports. Bark beetle infestations, spreading because of warmer winters and longer, warmer summers, are leaving acres of tinder-dry dead forest.

Nationally, climate change is being blamed for lengthening the nation's wildfire season, with scientists predicting larger and more frequent wildfires. The U.S. Forest Service says the wildfire season now averages 78 days longer than it did in the mid-1980s.

Fire models project more wildfire and increased risks to communities across extensive areas of the western U.S.

Drought/water issues -- Las Vegas and Los Angeles

The Southwest region is the hottest and driest in the USA, where the availability of water has defined its landscapes, history of human settlement and modern economy, the NCA reports. Climate changes pose challenges for an already parched region that is expected to get hotter and, in its southern half, significantly drier.

Increased heat and changes to rain and snowpack will send ripple effects throughout the Southwest, affecting 56 million people - a population forecast to increase to 94 million by 2050 - and its critical agriculture sector.

Severe and sustained drought will stress water sources, already overutilized in many areas, forcing increasing competition among farmers, energy producers, urban dwellers and ecosystems for the region's most precious resource.

Ocean acidification -- Seattle and Juneau, Alaska

Ocean acidification, the shifting of the ocean's water toward the acidic side of its chemical balance, has been driven by excess carbon dioxide in the ocean due to climate change. In the Northwest, ocean acidification threatens culturally and commercially significant marine species that are directly affected by changes in ocean chemistry (such as oysters) and those affected by changes in the marine food web (such as Pacific salmon).

Acidification has brought increasingly corrosive seawater to the surface along the West Coast and the inlets of Puget Sound, a center of the $111 million shellfish industry in the Pacific Northwest, for example.